APPENDICITIS Historical Perspective
In 1886, Reginald Fitz of Boston correctly identified the appendix as the primary cause of right lower quadrant inflammation. He coined the term appendicitis and recommended early surgical treatment of the disease. Richard Hall reported the first survival of a patient after removal of a perforated appendix, which launched focused attention on the surgical treatment of acute appendicitis. In 1889, Chester McBurney described characteristic migratory pain as well as localization of the pain along an oblique line from the anterior superior iliac spine to the umbilicus. McBurney described a right lower quadrant muscle-splitting incision for removal of the appendix in 1894. The mortality rate from appendicitis improved with the widespread use of broad-spectrum antibiotics in the 1940s. Recent advances have included improved preoperative diagnostic studies, interventional radiologic procedures to drain established periappendiceal abscesses, and the use of laparoscopy to confirm the diagnosis and exclude other causes of abdominal pain. Laparoscopic appendectomy was first reported by the gynecologist Kurt Semm in 1982 but has only gained widespread acceptance in recent years.
Pathophysiology
Obstruction of the lumen is believed to be the major cause of acute appendicitis.[2] This may be due to inspissated stool (fecalith or appendicolith), lymphoid hyperplasia, vegetable matter or seeds, parasites, or a neoplasm. The lumen of the appendix is small in relation to its length, and this configuration may predispose to closed-loop obstruction. Obstruction of the appendiceal lumen contributes to bacterial overgrowth, and continued secretion of mucus leads to intraluminal distention and increased wall pressure. Luminal distention produces the visceral pain sensation experienced by the patient as periumbilical pain. Subsequent impairment of lymphatic and venous drainage leads to mucosal ischemia. These findings in combination promote a localized inflammatory process that may progress to gangrene and perforation. Inflammation of the adjacent peritoneum gives rise to localized pain in the right lower quadrant. Although there is considerable variability, perforation typically occurs after at least 48 hours from the onset of symptoms and is accompanied by an abscess cavity walled-off by the small intestine and omentum. Rarely, free perforation of the appendix into the peritoneal cavity occurs that may be accompanied by peritonitis and septic shock and can be complicated by the subsequent formation of multiple intraperitoneal abscesses.
Bacteriology
The flora in the normal appendix is very similar to that in the colon, with a variety of facultative aerobic and anaerobic bacteria. The polymicrobial nature of perforated appendicitis is well established. Escherichia coli, Streptococcus viridans, and Bacteroides and Pseudomonas species are frequently isolated, and many other organisms may be cultured ( Table 49-1 ). Among patients with acute nonperforated appendicitis, cultures of peritoneal fluid are frequently negative and are of limited use. Among patients with perforated appendicitis, peritoneal fluid cultures are more likely to be positive, revealing colonic bacteria with predictable sensitivities.[3] Because it is rare that the findings alter the selection or duration of antibiotic use, some authors have challenged the traditional practice of obtaining cultures.
Diagnosis History
Appendicitis needs to be considered in the differential diagnosis of nearly every patient with acute abdominal pain. Early diagnosis remains the most important clinical goal in patients with suspected appendicitis and can be made primarily on the basis of the history and physical exam in most cases. The typical presentation begins with periumbilical pain (due to activation of visceral afferent neurons) followed by anorexia and nausea. The pain then localizes to the right lower quadrant as the inflammatory process progresses to involve the parietal peritoneum overlying the appendix. This classic pattern of migratory pain is the most reliable symptom of acute appendicitis.[5] A bout of vomiting may occur, in contrast to the repeated bouts of vomiting that typically accompany viral gastroenteritis or small bowel obstruction. Fever ensues, followed by the development of leukocytosis. These clinical features may vary. For example, not all patients become anorexic. Consequently, the feeling of hunger in an adult patient with suspected appendicitis should not necessarily deter one from surgical intervention. Occasional patients have urinary symptoms or microscopic hematuria, perhaps owing to inflammation of periappendiceal tissues adjacent to the ureter or bladder, and this may be misleading. Although most patients with appendicitis develop an adynamic ileus and absent bowel movements on the day of presentation, occasional patients may have diarrhea. Others may present with small bowel obstruction related to contiguous regional inflammation. Therefore, appendicitis needs to be considered as a possible cause of small bowel obstruction, especially among patients without prior abdominal surgery.
